Twitter has deleted tweets which were deemed important for investigators in the ongoing examination of Russia's suspected manipulation of the social network during the 2016 presidential election according to the US officials.

Twitter's policy means that once a user deletes a tweet, the tweets will be permanently deleted from Twitter's servers after 30 days through an automated process.

As a result, any of the account holders who deleted tweets and the accounts suspected of having spread false or exaggerated pro-Trump and anti-Clinton narratives, were also permanently deleted from Twitter's system.

A report by Politico also stated that Twitter policies read: “Content deleted by account holders (e.g., Tweets) is generally not available.”

This comes as a huge blow for US government as Twitter's vice president for Public Policy Colin Crowell earlier met with staff from Senate Select Committee on Intelligence and House Permanent Select Committee on Intelligence to discuss Russian interference in the 2016 U.S. election and offered continuous support to collaborate with investigators.

Thomas Rid, a Strategic Studies professor at Johns Hopkins University said: “Should bot operators and people who spread hate and abuse have the right to remove content from the public domain? Twitter says yes, and I think it’s a scandal.

“It removes forensic evidence from the public domain, and makes the work of investigators more difficult and maybe impossible.”